Brain-computer interfaces (BCI) represent a large growing area for biomedical device development. One of the goals of BCI devices is to assist patients with severe disabilities. The BCI devices provide direct or indirect reading of neural/neuronal activity through surface or implanted electrodes to obtain at least a 1-bit communication channel under the patient's control. Many brain-injured patients, who have suffered a brainstem stroke, hemorrhage, or axonal injury due to trauma that leads to partial or total paralysis may have injuries to brainstem and forebrain structures that control arousal level. Other patients can have severe damage to motor pathways at higher levels of the brain due a variety of brain insults. Moreover, damage to central motor control structures even without interruption of the motor pathways may produce such severely impaired motor control that clinical distinctions between true damage to motor pathways and motor preparation systems is hard to determine. Most conventional applications of BCI focus on reading in brain activity from a brain-injured subject for providing output to a prosthetic device such as a robot arm or a cursor on a computer screen. However, existing applications of BCI systems do not address the often critical problems of state control for arousal regulation of the forebrain created by the types of brain injuries that produce the need for a BCI. A common problem faced by these patients is a failure to maintain regulation of forebrain neuronal activity within wakeful states corresponding to a base vigilance level (specifically arousal level within the wakeful state) and consequent ability to maintain behavioral sets and complete intended behaviors due to impairment of frontal executive systems that support motor preparation, working memory, sustained attention, and goal-directed action and intentions. In the absence of such a base vigilance/arousal level (e.g., a patient falling back into minimally conscious state where intentions and actions are inconsistent or appear identically inconsistent to patients in minimally conscious state), the conventional BCI devices will fail to operate. In certain situations, such a lapse to a sub-threshold vigilance/arousal level will lead to functional failure of the BCI device. For example, if a patient controlling a prosthetic or an external communication device being operated using a BCI reduces their vigilance level to a point where control of the device is weak or absent, the patient will not be able to communicate or operate external prosthetics that may be controlled by the BCI. In other words, conventional BCI systems fail to link with and utilize the arousal mechanisms of the brain to maintain functional communication with external world through the BCI.
Therefore, there is a need in the current conventional technology to establish a patient-controlled Brain Computer Interface/arousal regulation (BCI/AR) system that adapts and accommodates the level of brain activation unique to a patient's use of the BCI to produce an effective communication channel with the outside world, to allow the patient with such problems to reliably and optimally stimulate subcortical regions of the brain and to communicate or control the BCI device itself and/or an external device/prosthetic attached to the BCI.
The present invention is directed to overcoming the above-noted and other deficiencies in the art.